1. Field of the Invention
This invention relates to bags, and, more particularly, to bags for secure deposit of articles.
2. Discussion of the Art
Security deposit bags are used to securely store and transport valuable articles such as documents, cash and currency, checks, jewelry, bank deposits, securities, criminal investigation evidence, and the like. Typically, security deposit bags include bags or envelopes constructed from sewn fabric, plastic film, or laminates thereof with a zippered closure. The zippered closure may be secured with a lock or seal. However, such conventional security deposit bags are bulky and expensive, and although they are reusable, they also generate a recurring expense in transporting the security deposit bag back to the sender for reuse.
Disposable security deposit bags that are adhesively secured and sealed have also been developed. U.K. Patent Application No. GB 2145997A, entitled "Tamperproof Bag", illustrates one such disposable bag, which is constructed of polyethylene. An adhesive strip is applied to an inside surface of the bag adjacent the opening and is temporarily covered by a liner. Once the bag has been filled, the liner is removed and the bag sealed by the adhesive strip. The bond of the adhesive strip exceeds the strength of the plastic film used to construct the bag. Any attempt to open the bag will result in destruction or visible distortion of the bag material, thus indicating that the bag has been opened. In another embodiment in U.K. Patent Application No. GB 2145997A, the bag comprises a flap that is intended to be folded over the opening to form a second seal. U.K. Patent Application No. GB 2120638A discloses a plastic security bag having one or more lines of adhesive extending from both edges of the bag inside the bag in such a way that the bag can be completely sealed against egress of contents. Although the security deposit bags disclosed in U.K. Patent Application Nos. GB 2145997A and GB 2120638A are improvements over other conventional security deposit bags, they still exhibit several undesirable characteristics. It has been found that by subjecting the adhesive seal of the bag to extremely low temperature, e.g., -45.degree. C., by means of dry ice or dichlorodifluoromethane ("Freon"), the adhesive becomes non-tacky, thereby allowing the adhesive to become unsealed from the polyethylene layer to which it has been applied. One can then tamper with the contents of the package and finally reseal the bag when the adhesive reaches ambient temperature.